/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.omid.tso;
  
  import org.apache.phoenix.thirdparty.com.google.common.base.Stopwatch;
  import org.apache.phoenix.thirdparty.com.google.common.base.Throwables;
  import org.apache.omid.metrics.MetricsRegistry;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.annotation.concurrent.NotThreadSafe;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import static org.apache.omid.metrics.MetricsUtils.name;
  import java.util.concurrent.TimeUnit;
  
  @NotThreadSafe
  public class MonitoringContextImpl implements MonitoringContext{
  
      private static final Logger LOG = LoggerFactory.getLogger(MonitoringContextImpl.class);
  
      private volatile boolean flag;
      private Map<String, Long> elapsedTimeMsMap = new ConcurrentHashMap<>();
      private Map<String, Stopwatch> timers = new ConcurrentHashMap<>();
      private MetricsRegistry metrics;
  
      public MonitoringContextImpl(MetricsRegistry metrics) {
          this.metrics = metrics;
      }
  
      public void timerStart(String name) {
          Stopwatch stopwatch = Stopwatch.createStarted();
          timers.put(name, stopwatch);
      }
  
      public void timerStop(String name) {
          if (flag) {
              LOG.warn("timerStop({}) called after publish. Measurement was ignored. {}", name, Throwables.getStackTraceAsString(new Exception()));
              return;
          }
          Stopwatch activeStopwatch = timers.get(name);
          if (activeStopwatch == null) {
              throw new IllegalStateException(
                      String.format("There is no %s timer in the %s monitoring context.", name, this));
          }
          activeStopwatch.stop();
          elapsedTimeMsMap.put(name, activeStopwatch.elapsed(TimeUnit.NANOSECONDS));
          timers.remove(name);
      }
  
      public void publish() {
          flag = true;
          for (Map.Entry<String, Long> entry : elapsedTimeMsMap.entrySet()) {
              metrics.timer(name("tso", entry.getKey())).update(entry.getValue());
          }
      }
  
  }